1. Field of the Invention
The invention relates to a catch between two objects that are moveable in relation to one another and particularly to a door catch.
2. Description of the Related Art
German reference DE 15 29 716 A1 discloses a hydropneumatic lifting unit having a hydraulic lock. The lifting unit has a working chamber, in which a working piston can perform an operating movement. An arbitrarily activatable friction element, the friction force of which is generated by an increase in volume, is arranged between the working piston and a wall which defines the working chamber. The increase in volume is achieved by feeding hydraulic medium into the elastically expandable friction element designed as hollow body.
German reference DE 199 10 782 A1 describes a door hinge having a cylinder which is filled with an electrorheological fluid. A piston formed as a vane divides the cylinder into at least two working chambers. A flow connection between the working chambers is subject to the influence of an electrical field, so that by varying the viscosity of the fluid inside the flow connection, a locking action is achieved. The retaining force of the door catch may be increased by designing the flow connection with the longest possible dimension. Such a design, however, limits the maximum swivel angle of the door hinge, since the flow connection is formed by a gap between the vane and the wall of the cylinder.